JEE Main20198 Apr 2019Evening ShiftMathematicsMathematical ReasoningActual
Which one of the following statements is not a tautology?
Options
- Ap ∨ q → p ∨ ( ~ q )
- Bp ∧ q → ( ~ p ∨ q )
- Cp → p ∨ q
- Dp ∧ q → p
Correct answer
A. p ∨ q → p ∨ ( ~ q )
Step-by-step solution
Logical Statement p → q is false if and only if p is true and q is false. So, when p is false, q is true, p ∨ q → p ∨ ~ q will be false. Clearly p ∨ q → p ∨ ~ q is not a tautology.